Electronic floor leveler for elevators



y 1945. w. MULLER ELECTRONIC FLOOR LEVELER FOR ELEVATORS Filed Sept. 29, 1944 2 Sheets-Sheet 1 INVENTOR. BY li hwer flail kwkmmk May 8, 1945. w L R 2,375,435

ELECTRONIQFLOOR LEVELER FOR ELEVATORS Filed Sept. 29, 1944 2 Sheets-Sheet 2 TECE/VE]? Z INVENTOR.

il rner fla/Zzr flun a? HTTOR/VEY Patented May 8, 1945 ELECTRONIC FLOOR LEVELER FOR ELEVATORS Werner Muller, New York, N. Y., assignor to Brujac Electronic Corporation, New York, N. Y., a corporation of New 'York Application September 29, 1944, Serial No. 556,337

11 Claims.

The present invention relates to the art of automatic elevator control, and, more particularly, to an electronic floor leveler for elevators, and the like.

It is an object of the present invention to provide improved control of elevator operation including stopping the elevator car at the exact level of one of the landings.

It is another object of the present invention to provide a novel and improved device for controlling the raising and lowering of the elevator car whereby upon arrival of the car in proximity to one of the landings, the car is automatically displaced in the upward or downward direction until it has been brought to the exact landing level.

It is a further object of the invention to provide an electronic control device for automatic floor leveling of elevators including a transmitter of high-frequency energy and a pair of receiver for such energy adapted to be selectively actuated for causing upward or downwards operation of the driver motor until a balanced condition and exact leveling of the elevator car are obtained.

It is also within the contemplation of the invention to provide an electronic floor leveler system for elevators, and the like, in which radiofrequency transmitting and receiving means are arranged in the elevator car, said means being adapted to cooperate with stationary means arranged in the elevator shaft, causing transfer of radio-frequency energy from the transmitter to one of the receivers in accordance with the relative position of the car with respect to the landmg.

The invention also contemplates an electronic elevator floor leveler based upon the selective transmission of impulses from a. radio-frequency transmitter to a pair of receivers by means of stationary capacitive elements arranged in proximity to each of the landings, which is very simple in construction, satisfactory and foolproof in its operation, and which may be readily manufactured and employed on a practical and industrial scale at a low cost.

Other and further objects and advantages of the invention will become apparent from the following. description, taken in conjunction with the accompanying drawings; in which Fig. 1 illustrates a side elevational view, having parts in section, of an electronic floor leveler system embodying the principles of the present invention,

Fig. 2 depicts asimilar elevational view, somewhat fragmentary in character, of the control box including the electronic equipment of the system together with its capacitive control electrodes;

Fig. 3 shows a sectional view on line 33 of Fig. 2 through one of the control electrodes with its tuning coil and mechanical adjusting means; and

Fig. 4 is a circuit diagram illustrating a preferred form of circuit organization of the electronic control device of the invention.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In the following description and in the claims, parts will be identified by specific names, for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Broadly stated, in accordance with the principles of the invention, there is provided in combination with the elevator car a transmitter of radio-frequency energy and a pair of receivers for such energy, said transmitter and receivers being displaced in the elevator shaft concurrently with the displacement of the elevator car. The transmitter and the receivers are operatively associated with coupling elements which are arranged in close proximity to one of the sides of the shaft and are adapted to cooperate with stationary coupling elements mounted in the shaft at each landing. Upon approach of the elevator car to one of the said landings, the stationary coupling element willbecome effective to transfer radio-frequency energy from the transmitter to one of the two receiversin accordance with the momentary position of the elevator car with respect to such landing. In accordance with the receiver energized, suitable control or switching means become efiective, causing the driver 'motor to move the car in the upward or downward direction until a balanced condition is obtained in which the elevator car is stopped. Generally speaking it is preferred to employ the automatic fioorleveler of the invention in combination with manually operable control elements for the driver motor. These control elements are automatically disabled when the car approaches one of the landings and leave the car to the sole control .of the floor leveler equipment. I

Referring now more particularly to the drawings, the mechanical construction and arrangement of the automatic floor leveler of the invention will be best understood by reference to Figs. 1 and 2 of the drawings. Reference character l denotes the top of the elevator car upon which thereis mounted a bracket II by means of nuts l2. To this bracket there is secured a control box generally denoted by reference character l3, preferably made of metal, housing the elements of the electronic circuits constituting the control system. The control box is covered by means of a metal cover plate M which provides mechanical protection and at the same time electrostatic shielding forthe electronic circuits. Cover plate I4 is provided with three circular openings |5, I6 and N, (Fig. 2) through which there are exposed control electrode plates l8, l3, and 28, respectively. Of these, the center one is operatively associated with the transmitter of radio-frequency energy while the upper and lower ones are respectively associated with two receivers for such energy. These control plates are arranged for cooperation with a stationary control member or plate 2| provided in the form of an elongated metal plate having a pin 22 secured to each end thereof, said pins being slidably mounted in insulative \bosses 23 provided on one sid 24 of the walls of the elevator shaft. Coil springs 25 around pins 22 between boss 23 and plate 2| resiliently hold the said control plate in a position in which it is closely spaced to plate l4 of the control box without, however touchmg the same. It will be noted that stationary control plate 2| is capable of slight displacement against the pressure of the springs in the event that plate |4 would strike against the same during their relative displacement. Preferably, control plate 2| is fully covered by means of a suitable insulating material 26, such as Bakelite, Textolite, and the like. A readily yielding elastic member or bumper 21 constituted of sponge rubber, or the like, may be provided at either end of the said plate to prevent mechanical shock of the control plate by accidental contact thereof with cover plate H of the control box and at the same time remove dirt or dust, which may accumulate on the surface of the cover plate during the operation of the device. Openings |5, Hi and IT in cover plate l4 of the control box may 'be covered by a thin sheet or plate of insulating material (not shown), if desired, to prevent the entrance of dust into the box without interfering with the capacitive cooperation of control electrode plates I8, l3 and 20 with stationary plate 2|. The relative position of stationary control plate 2| with respect to door 28, and that of control box I3 with respect to elevator car ID are so determined that when the said control plate is symmetrically positioned with respect to the control box and to the three control electrodes l8, l9, and 28 therein, door 28 of the shaft is accurately aligned with the door 01' the car.

The electronic circuits forming part of the control device of the invention will be best understood from Fig. 4. These circuits are energired from the direct or alternating current power line connected to terminals 30. A switch 3| is inserted in one of the leads .connected to plates 32 of a rectifier tube 33 and is also grounded through a small by-pass condenser 34. Cathodes 35 of the rectifier tube are connected through filter resistances 36 and 31 to point 38, which constitutes the B plus terminal of the power pack. Filter condensers 33, 40 and 4| are connected between cathodes 35, the common terminals of resistances 38 and 31, B plus terminal 38, and ground, respectively.

The radio-frequency transmitter is built around a screen-grid tube 42, cathode 43 of which is grounded. Control grid 44 of the said tube is connected through a tuning condenser 45 and a tuning coil 46 to ground, while its screen grid 41 is connected through a coupling coil 48 to B plus terminal 38. Coils 46 and 48 are coupled to each other and constitute a high-frequencytransformer 43. Plate 50 is connected to the B plus terminal through a coil 5| and through coil 48. The radio-frequency oscillatory energy is withdrawn at the plate an is applied to capacitor electrode I8 through a coupling condenser 52.

Receiver I includes a radio-frequency amplifier tube 60 of the screen-grid type having a control grid 6|, which is directly connected to capacitor .plate l8. A tuning coil 82 is connected between the said grid and ground and is so dimensioned as to be resonant to the radio-frequency oscillations produced by the transmitter. Cathode 63 is grounded through a biasing resistor 64 having a by-pass condenser 65 connected across the same. Screen-grid 88 is connected to the B plus terminal 38.

Tube is coupled to detector tube 61 by means of a high-frequency transformer 88, having a tuned primar circuit 69 and a tuned secondary circuit 10. Tuned circuit 69 is connected between plate ll of tube GI and B plus, while tuned circuit I0 is connected between grid 12 of tube 61 and ground. Of course, the said tuned circuits are inductively coupled with each other, such couplin bein supplemented by means of a coupling condenser 13, establishing direct capacitive connection between the plate of the amplifier tube and the grid of the detector tube. Cathode 14 of the detector tube is connected to ground through biasing resistance 15 having a by-pass condenser 16 connected across the same. Plate ll of the said tube is connected to B plus through operating coil 18 of a relay l8, and a condenser 80 is connected between plate 17 and ground for bypassing the high-frequency oscillations.

Receiver 2 is identical in its circuit arrangement with receiver and similar reference characters 60 to 80 have [been employed to denote parts corresponding to elements 80 to 80 of receiver I. It will be noted that capacitor plate 28 is connected to grid 6| of tube 60 and that operating coil 18 of relay 19' is connected to plate 11 of detector tube 61' and B plus. Tube 61 is jointly (biased with tube 61 of receiver I by means of cathode resistance 15.

Relay I9 is provided with a pair of normally open contacts 8| and 82 and relay 19' is provided with a pair of similar normally open contacts 8 and 82'. The said contacts are operatively associated with a differential relay 96 having a pair of windings 83 and 83'. Contacts 82 and 82 of relays 19 and 19' are connected to B plus, while contacts 8| and 8| of the same relays are respectively connected to one end of coils 83 and 83 of the differential relay. The other ends of coils 83 and 83' are jointly connected to ground. The coils of the differential relay are adapted to attract one end of an armature 84 pivotally mounted in its center, the said armature being turned clockwise and anti-clockwise according to whether coil 83' or coil 83 of the relay is energized. Armature 84 is mechanically connected with a pair of switching arms 85 and 86 of which 85 is capable of selective cooperation with contacts 81 and 88 and 86 is capable of similar cooperation with contacts 83 and 80 in the deflected positions of the armature, while in the illustrated center position of the armature, the switching arms are disconnected from all of the contacts. Switching arms 85 and 86 are connected to the two ends of field coil 9| of the driver electromotor and contacts 81 and 90 are connected together and to terminal 92 of the power line. Contacts 88 and 89 are likewise connected together and to one end of armature winding 94 of the motor, the other end of which is connected to terminal 93 of the power line.

From the foregoing description, the operation of the electronic fioor leveler of the invention will be readily understood by those skilled in the art. It is to be observed at the outset that all of the tubes forming part of the transmitter and receivers described in the foregoing are provided with conventional heaters for heating their cathodes to electron-emitting operating temperatures and that the wiring of the said heaters has been omitted from the circuit diagram in view of its conventional character. It will be also noted that the transmitter is shown as a conventional electron-coupled oscillator which is producing radiofrequency oscillations in a manner Well understood. Preferably, the transmitter is tuned to an operating frequency of about 100 to 300 kilocycles although, of course, other suitable radiofrequencies may be employed with equal or simi-- lar results, It may be likewise assumed that driving motor 9|, 94 of the elevator may be also energized from other switching means independent from differential relay 96 to cause displacement of the elevator car between the several fioors, such switching means being disabled upon the car approaching the landing where the car is to be stopped so that from that point on the car and its driving motor are solely under the control of differential relay 96.

Assuming now that the elevator car is being raised, control box I3 with capacitor plates I8, I9 and 28 will be raised therewith and will arrive in a position in which capacitor plate I8 connected to receiver I and capacitor plate I9 connected to the transmitter will arrive into a closely spaced position with respect to stationary capacitor plate 2|, while capacitor plate 28 connectedto receiver 2 will be still at some distance from the stationary plate. Plates I8 and III will be coupled to each other by means of the stationary plate so that radio-frequency energy will be transferred from the transmitter to receiver I. The received signal will be amplified by tube of the differential relay will bring armature 84 into its neutral or center position in which switching arms 85 and 86 are disconnected from the contacts, thus disabling the driving motor so that the elevator car will be stopped at the exact landing position in which door 28 of the shaft is aligned with the door of the car.

Substantially the same operative sequence occurs when the elevator car is lowered. In this case, capacitor plates 28 and I9, respectively connected to receiver 2 and to the transmitter, will first arrive into cooperating position with Stationary capacitor plate 2|, Radio-frequency energy will be transferred from capacitor plate I9 to capacitor plate 28, such energy, being amplified and detected in receiver 2, will energize relay I9. This relay will close its contacts 8| and 82' and will complete the circuit of coil 83' of the differential relay. Armature 84 of the said relay will be displaced in the clockwise direction transferring switching arms 85 and 86 into their lower position in which they make with contacts 88 and 98, respectively, and thus close the circuit of motor 9 I, 94. The motor circuit will now be from terminal 92 of the power line, through contact 98, switching arm 86, field coil 9|, switching arm 85, contact 88, armature 94, and back to the other terminal 93 of the power line. It will be noted that in this case the field coil of the motor will be energized in a direction opposite to that when relay I9 is energized, so that the elevator car will be further lowered. This will continue until all capacitor plates 28, I9 and I8 will be brought into cooperating position with stationary plate 2|, when both relays I9 and I9 will be energized and the differential relay will be returned into its neutral position, stopping further rotation of the motor. It is preferred to provide for adjustment of capacitor plates I8, I9 and 28 in order to bring them to the desired distance from stationary capacitor plate 2| in the operative position of the plates. This adjustment may be accomplished,

68 and rectified 0r detected by tube 61 so that relay I9 will be energized and its contacts 8| and 82 will be closed. This in turn will close the circuit of coil 83 of differential relay 96 so that its armature 84 will be turned in the anti-clockwise direction, transferring switching arms 85 and 86 from their open center position into their upper position in which they respectively make with contacts 81 and 89. This will close the circuit of motor 9|, 94, such circuit being from terminal 92 of the power line, through contact 8], switching arm 85, field coil 9|, switching arm 86, contact 89, armature 94, and to the other terminal 93 of the'power line. In this position of the differential relay, the motor will be energized to further raise the elevator car. This displacement will be continued until such time as all three capacitor plates I8, I9 and 28 arrive into cooperating position with stationary capacitor plate 2|.

for example, by means of the structure illustrated in Fig. 3. A metal shield can I88 having a center opening |8I therein is secured to cover plate I4 of control box I3 by means of nuts and bolts I82 so as to cover opening l5. A circular insulative plate I83 having 3.3:. internally threaded metal bushing I84 in the center thereof is secured by rivets. I85 to shield can I88 to cover opening I8I. Rivets I85 also hold a pair of light brackets I86, supporting cylindrical coil form I81 with coil 62 thereon. In bushing I84 there is inserted the lower threaded end of a met afrod I88 bearmg capacitor plate I8 at its upper end. A screwdriver slot I89 in rod I 88 facilitates rotation of the rod, whereby the position of the capacitor plate with respect to'cover plate I4 may be accurately adjusted and thus the desired operating conditions obtained. One end of coil 62 is connected to capacitor plate I8 by means of a flexible cable II8 soldered to rod I88 at III, said cable being long enough to permit rotation of the plate I 8 to the extent of a few revolutions. The other end of coil 62 is connected to flexible cable I I2, which is passed through opening 3 provided in shield can I88 for this purpose.

although the present invention has been described in connection with a preferred embodiment thereof, variations and modifications may be resorted to by those skilled in the art without departing from theprinciples of the present invention. Thus, while the operation of the present embodiment of the invention is based upon the cooperation of capacitive coupling means, such as displaceable and stationary capacitor plates, in predetermined positions of the elevator car, inductive coupling means may be employed with equal or similar results. Numerous variations are also possible in the circuit organization of the transmitter, of the receiver, and of the switching means for the driving motor. All of these variations and modifications are considered to be within the true spirit and scope of the present invention, as disclosed in the foregoing description and defined by the appended claims.

What is claimed is:

1. An elevator control system which comprises in combination a displaceable transmitting coupling element and a pair of displaceable receiving coupling elements mounted on an elevator car for joint displacement therewith, a source of radiofrequency energy connected to said transmitting element, a pair of receivers for such energy respectively connected to said receiving elements, stationary couplingelements for selective cooperation with said transmitting element and at least one of said receiving elements, and means under the control of said receivers to energize driving means for the car in accordance with the relative position of said displaceable coupling elements with respect to said stationary coupling element.

2. An elevator control system which comprises in combination a displaceable transmitting coupling member and a pairof displaceable receiving coupling members mounted on an elevator car for joint displacement therewith, said receiving members being spacedly disposed with respect to each other in the direction of the elevator travel and having said transmitting member therebetween, a radio-frequency oscillator of substantially constant frequency connected to said transmitting member, a pair of receivers tuned to such frequency respectively connected to said receiving members, a stationary coupling member for selective cooperation with said transmitting member and at least one of said receiving members to transfer oscillatory energy from said oscillator to one of said receivers, and. driving means for said car under control of the output of said receivers to displace the car until balanced amounts of oscillatory energy are received by both receivers.

3. An elevator control system which comprises in combination a displaceable transmitting capacitor plate and a pair of displaceable receiving capacitor plates insulatedly mounted on an elevator car for joint displacement therewith, said receiving plates being spacedly disposed with respect to each other in the line of travel of said car and having the transmitting plate therebetween, a radio-frequency oscillator of substantially constant frequency energizing said transmitting plate, a pair of receivers tuned to such frequency respectively connected to said receiving plates, a stationary capacitor plate adapted to couple at least one of said receiving plates to said transmitting plate during the travel of said car and thereby to impress a signal upon the receiver associated with said receiving plate, driving means for said car, and control means for said driving means operable by the output of said receivers to actuate the driving means in one direction when a signal is impressed upon one of said receivers and to actuate the driving means in the opposite direction when a signal is impressed upon the other one of said receivers.

4. An elevator control system which comprises in combination three displaceable capacitor plates spacedly and insulatedly mounted on an elevator car in the line of travel thereof, a radio-frequency transmitter connected to the center one of said plates, a receiver connected to each of the other two of said plates, an elongated stationary capacitor plate mounted in the elevator shaft constructed and arranged for spaced capacitive cooperation with said displaceable plates in predetermined positions of said car in the shaft to transfer a signal from said transmitter to at least one of said receivers, driving means for said car, and control means for saiddriving means operable by the output of said receivers to actuate the driving means in one direction when a signal is impressed upon one of said receivers, to actuate the driving means in the opposite direction when a signal is impressed upon the other of said receivers, and to disable said driving means when a signal is impressed upon both of said receivers.

5. An elevator control system which comprises in combination three displaceable capacitor plates insulatedly mounted in uniformly spaced relation on an elevator car in the line of travel thereof, a radio-frequency oscillator connected to the center one of said plates and a receiver connected to each of the other two of said plates, an elongated stationary capacitor plate mounted in the elevator shaft in proximity to each landing in substantially parallel-spaced position with said displaceable plates adapted to capacitively couple said oscillator to at least one of said receivers upon approach of the car to the landing from either direction, a driving motor for said car, and control means for said motor differentially operable by the output of said receivers to cause displacement of the car and of the capacitor plates thereon until substantially balanced signals are impressed upon both receivers and to stop the motor when such balanced condition is obtained.

6. An elevator control system which comprises in combination three displaceable capacitor plates insulatedly mounted in uniformly spaced relation on an elevator car in the line of travel thereof, a radio-frequency oscillator connected to the center one of said plates and a receiver connected to each of the other two of said plates, an elongated stationary capacitor plate mounted in the elevator shaft in proximity to each landing to establish selective capacitive coupling between the oscillator and one of the receivers in accordance with the direction of approach of the car to said landing and to establish such coupling between the oscillator and both receivers in the exact landing position of the car, driving means for said car, and control means for said driving means operable by the output of said receivers to displace the car towards the position in which the stationary plate couples both receivers to the oscillator and to disable the driving means when such position has been obtained.

'7. An elevator control system which comprises in combination three traveling capacitor plates insulatedly mounted in spaced relation on an elevator car in the line of travel thereof and facing one of the walls of the elevator shaft, an oscillator connected to the center one of said plates and a receiver responsive to the output of said oscillator connected to each of the other two plates, an elongated stationary capacitor plate insulatedly mounted in the shaft in proximity to each landing arranged for parallel-spaced cooperation with said traveling plates to establish selective capacitive coupling between the oscillator and one of the receivers in accordance with the direction of approach of the car to said landing and to establish such coupling between the oscillator and both receivers in the exact landing position, means for adjusting the relative position of said stationary and traveling capacitor plates, driving means for said car,and control means for said driving means operable by the output of said receivers to displace the car towards the position in which the stationary plate couples both receivers to the oscillator and to disable the driving means when such position has been obtained.

8. The elevator control system claimed in claim '7 wherein the stationary capacitor plate is resiliently mounted.

9. The elevator control system claimed in claim '7 wherein the stationary capacitor plate is covered with an insulative layer.

10. In an automatic floor leveler for elevators,

and the like, having driving means for the elevator car and control means for said driving means, the improvement which comprises a transmitter and a pair of receivers of radio-frequency energy in said car, coupling elements on said car and at each landing in the elevator shaft adapted to cooperate with each other upon approach of the car to a landing to selectively couple the transmitter to one of the receivers in accordance with the direction of such approach and to both of the receivers in the landing position, and means responsive to the output of the said receivers to differentially actuate the said control means for displacement of the car towards the nearest landing position and to disable the driving means in said position.

11. In an automatic floor leveler for elevators, and the like, having driving means for the elevator car and control means for said driving means, the improvement which comprises a generator of constant-frequency oscillations and a pair of receivers for such oscillations in said car,

-a plurality of capacitor plates on said car and a capacitor plate in the elevator shaft at each landing, said plates being adapted to cooperate with each other upon approach of the car to a landing to selectively couple the generator to one of the receivers in accordance with the direction of such approach and to both of the receivers in the landing position, and means responsive to the output of said receivers to differentially actuate the said control means for displacing the ear towards the nearest landing position and to disable the driving means when the landing position has been obtained.

WERNER MULLER. 

